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authorSteven Rostedt <srostedt@redhat.com>2012-03-27 10:43:28 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-13 08:33:47 -0700
commit7be29c2aabb07d7964600f2ffda281a349642efe (patch)
tree32d47321b9d53fd9d6514aea5bb4fb8b2477db14 /kernel
parenta4c3bcc7b26896c0d85a145f1ae08b12b8760e29 (diff)
tracing: Fix ent_size in trace output
commit 12b5da349a8b94c9dbc3430a6bc42eabd9eaf50b upstream. When reading the trace file, the records of each of the per_cpu buffers are examined to find the next event to print out. At the point of looking at the event, the size of the event is recorded. But if the first event is chosen, the other events in the other CPU buffers will reset the event size that is stored in the iterator descriptor, causing the event size passed to the output functions to be incorrect. In most cases this is not a problem, but for the case of stack traces, it is. With the change to the stack tracing to record a dynamic number of back traces, the output depends on the size of the entry instead of the fixed 8 back traces. When the entry size is not correct, the back traces would not be fully printed. Note, reading from the per-cpu trace files were not affected. Reported-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f2bd275bb60f..697e49d72503 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1642,6 +1642,7 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
int cpu_file = iter->cpu_file;
u64 next_ts = 0, ts;
int next_cpu = -1;
+ int next_size = 0;
int cpu;
/*
@@ -1673,9 +1674,12 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu,
next_cpu = cpu;
next_ts = ts;
next_lost = lost_events;
+ next_size = iter->ent_size;
}
}
+ iter->ent_size = next_size;
+
if (ent_cpu)
*ent_cpu = next_cpu;